Commit a9730fca authored by Christoph Lameter's avatar Christoph Lameter Committed by Linus Torvalds
Browse files

Fix kmalloc slab creation sequence 



This patch restores the slab creation sequence that was broken by commit
4066c33d and also reverts the portions that introduced the
KMALLOC_LOOP_XXX macros. Those can never really work since the slab creation
is much more complex than just going from a minimum to a maximum number.

The latest upstream kernel boots cleanly on my machine with a 64 bit x86
configuration under KVM using either SLAB or SLUB.

Fixes: 4066c33d ("support the slub_debug boot option")
Reported-by: default avatarTheodore Ts'o <tytso@mit.edu>
Signed-off-by: default avatarChristoph Lameter <cl@linux.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 88793e5c

include/linux/slab.h

+0 −22
Original line number Original line Diff line number Diff line
@@ -153,30 +153,8 @@ size_t ksize(const void *); 
#define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN

#define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN

#define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN

#define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN

#define KMALLOC_SHIFT_LOW ilog2(ARCH_DMA_MINALIGN)

#define KMALLOC_SHIFT_LOW ilog2(ARCH_DMA_MINALIGN)

/*

 * The KMALLOC_LOOP_LOW is the definition for the for loop index start number

 * to create the kmalloc_caches object in create_kmalloc_caches(). The first

 * and the second are 96 and 192. You can see that in the kmalloc_index(), if

 * the KMALLOC_MIN_SIZE <= 32, then return 1 (96). If KMALLOC_MIN_SIZE <= 64,

 * then return 2 (192). If the KMALLOC_MIN_SIZE is bigger than 64, we don't

 * need to initialize 96 and 192. Go directly to start the KMALLOC_SHIFT_LOW.

 */

#if KMALLOC_MIN_SIZE <= 32

#define KMALLOC_LOOP_LOW 1

#elif KMALLOC_MIN_SIZE <= 64

#define KMALLOC_LOOP_LOW 2

#else

#define KMALLOC_LOOP_LOW KMALLOC_SHIFT_LOW

#endif



#else

#else

#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)

#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)

/*

 * The KMALLOC_MIN_SIZE of slub/slab/slob is 2^3/2^5/2^3. So, even slab is used.

 * The KMALLOC_MIN_SIZE <= 32. The kmalloc-96 and kmalloc-192 should also be

 * initialized.

 */

#define KMALLOC_LOOP_LOW 1

#endif

#endif





/*

/*

mm/slab_common.c

+16 −16
Original line number Original line Diff line number Diff line
@@ -855,6 +855,12 @@ void __init setup_kmalloc_cache_index_table(void) 
	}

	}

}

}





static void new_kmalloc_cache(int idx, unsigned long flags)

{

	kmalloc_caches[idx] = create_kmalloc_cache(kmalloc_info[idx].name,

					kmalloc_info[idx].size, flags);

}



/*

/*

 * Create the kmalloc array. Some of the regular kmalloc arrays

 * Create the kmalloc array. Some of the regular kmalloc arrays

 * may already have been created because they were needed to

 * may already have been created because they were needed to
@@ -864,25 +870,19 @@ void __init create_kmalloc_caches(unsigned long flags) 
{

{

	int i;

	int i;





	for (i = KMALLOC_LOOP_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {

	for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {

		if (!kmalloc_caches[i]) {

		if (!kmalloc_caches[i])

			kmalloc_caches[i] = create_kmalloc_cache(

			new_kmalloc_cache(i, flags);

						kmalloc_info[i].name,

						kmalloc_info[i].size,

						flags);

		}





		/*

		/*

		 * "i == 2" is the "kmalloc-192" case which is the last special

		 * Caches that are not of the two-to-the-power-of size.

		 * case for initialization and it's the point to jump to

		 * These have to be created immediately after the

		 * allocate the minimize size of the object. In slab allocator,

		 * earlier power of two caches

		 * the KMALLOC_SHIFT_LOW = 5. So, it needs to skip 2^3 and 2^4

		 * and go straight to allocate 2^5. If the ARCH_DMA_MINALIGN is

		 * defined, it may be larger than 2^5 and here is also the

		 * trick to skip the empty gap.

		 */

		 */

		if (i == 2)

		if (KMALLOC_MIN_SIZE <= 32 && !kmalloc_caches[1] && i == 6)

			i = (KMALLOC_SHIFT_LOW - 1);

			new_kmalloc_cache(1, flags);

		if (KMALLOC_MIN_SIZE <= 64 && !kmalloc_caches[2] && i == 7)

			new_kmalloc_cache(2, flags);

	}

	}





	/* Kmalloc array is now usable */

	/* Kmalloc array is now usable */

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